Abstract: With further developments in cloud computing, data sharing has never been easier and a further review on the data sharing provides results which can be advantageous both to the society and individuals. When considering a large number of users, data sharing needs to take into account issues like optimisation, data integrity and secrecy of the data owned. One of the methods to do this is Ring Signature which proves to be promising. The main advantage is that it helps in creating an anonymous and genuine data sharing system. It further provides the owner of the data to anonymously authenticate his/her data which can be further put in cloud for further review later. The disadvantage for the Ring Signature is the expensive certificate verification in the traditional public key infrastructure (PKI). To overcome this disadvantage, Identity-based (ID-based) ring signature can be used which eliminates the process of certificate verification. This paper discusses about enhancing the security of the ID-based ring signature further by providing forward security. Considering a scenario wherein the secret key of a specific user is compromised then what is done is that all the previously generated signatures will still remain valid. By doing this, we eliminate the tedious job of re-authenticating the secret key of the user in question. This proves to be advantageous in cases where there is large scale data sharing. This paper further discusses about increasing the efficiency, security and provides algorithms so as to implement the system and show its practicality.
Keywords: cloud computing, smart grid, Ring signature, Forward Security.